Hydrogen production by NH₃ decomposition at low temperatures assisted by surface protonics

Area of Science:

• Catalysis
• Materials Science
• Electrochemistry

Background:

• Ammonia (NH3) is a promising hydrogen carrier due to its high hydrogen density and ease of transport.
• Current ammonia decomposition methods require high temperatures (>773 K), limiting practical applications.
• Developing efficient low-temperature ammonia decomposition is crucial for hydrogen production.

Purpose of the Study:

• To investigate the use of an applied electric field to enhance ammonia decomposition at lower temperatures.
• To explore the catalytic activity of Ru/CeO2 for this process.
• To understand the reaction mechanism under electric field influence.

Main Methods:

• Utilized a highly active Ru/CeO2 catalyst for ammonia decomposition.
• Applied an external electric field to the catalytic system.
• Conducted experiments at temperatures as low as 398 K.
• Employed neural network potential studies to elucidate the reaction mechanism.

Main Results:

• Achieved high ammonia conversion at significantly reduced temperatures (<773 K).
• Observed that the applied electric field lowers apparent activation energies.
• Demonstrated conversion surpassing equilibrium limits at 398 K.
• Identified HN-NH intermediate formation as key to the reaction mechanism.

Conclusions:

• An applied electric field combined with a Ru/CeO2 catalyst enables efficient low-temperature ammonia decomposition.
• This approach offers a feasible and economically attractive pathway for CO2-free hydrogen production.
• The reaction mechanism involves surface protonics and HN-NH intermediate formation.